1. Field of the Invention
The present invention applies to trigger-operated portable electric tools. More specifically, it concerns the field of portable electric tools that are controlled during use by a trigger activated by at least one finger of the hand holding said tools. By pressing on this trigger, a command is given to an actuator (often consisting of an electric motor) to activate the element or moving active elements of the tool in a given direction; by letting go of said trigger, a command is given to the actuator either to stop (for tools operating in a single direction) or to activate the element or moving active elements of the tool in the opposite direction (for tools operating in two directions).
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
Motorized pruning shears, especially electric and electronic pruning shears, are examples of contemporary tools having a bidirectional control trigger (opening and closing the cutting elements).
The applications of the invention described below apply especially to electronic pruning shears, but it is important to note that the invention can also be applied to other types of motorized pruning shears and to other types of trigger-operated tools, such as shears, drills, grinders, planes, and so on.
In their most advanced versions, such tools are provided, in addition to their principal function, with at least one additional function. This second function consists of, for example, in the ability to maintain an intermediary speed or position, or to reverse the direction of the motor, or to place the tool on standby.
This second function is controlled by the addition of a control device distinct and separate from the trigger, such as a pushbutton, a switch, and so on, positioned on the body of the tool, this device being intended to be activated by a finger other than the one that acts on said trigger.
However, this situation has the disadvantage of being uncomfortable for the user when operating the tool, for the user must either employ two fingers from one hand at the same time or, if the distance between these two control elements is too great, use his other hand, which results in a loss of time.
For example, many pruning shear models, in addition to the function of opening and closing the cutting elements controlled by a trigger activated by the user's finger, are equipped with a second function performed by an electrical or electronic system that can be used to arrest the rotation of the moving blade in a predetermined position intermediate between the closed position and the fully open position, thereby providing the ability to limit the opening of the blades, which is desirable in certain situations, for example, when cutting kindling wood, or when pruning, in order to save time and energy. This second function is controlled by a switch that is independent of the control trigger and must be activated by a finger other than the one used to activate said control trigger, and this must occur each time the operator wishes to go from the “fully open” position to the “intermediate” position and vice versa.
The transition from one position to another being frequent due to the varying thicknesses of wood being cut on the same plant, it is easy to imagine the inconvenience and loss of time occasioned by such a device.
An object of the invention is to correct the aforementioned drawbacks and inadequacies of portable electric tools, especially electric pruning shears.